2022 Volume 27 Issue 1 Pages 101-111
Members of the family Flabelligeridae are distributed worldwide, inhabiting the underside of rocks or within mixed sand sediments. Some genera of the family have gelatinous tunics with hooked chaetae. The genus Flabelligera Sars, 1829 is one of the members of the gelatinous free-living groups of Flabelligeridae. A fan-shaped cephalic cage, thick gelatinous tunic, and hooked neurohooks distinguish members of this genus. In Japan, Flabelligera affinis Sars, 1829 [Japanese name: Kanten-habouki] has been known as the sole Japanese species of Flabelligera inhabiting several locations. We reviewed Japanese species of Flabelligera from several sites from Hokkaido to Honshu and concluded that the Japanese “F. affinis” contained at least five different species under the specific name. In this study, we described them as five new species. All new species were collected from the underside of rocks in shallow to deep-sea depths. We have also provided mitochondrial cytochrome c oxidase subunit I sequences for DNA barcodes of the new species.